It would appear that lots of people and their (respective?) grandmas (if they like physics) want to do something within "string theory, cosmology or particle physics". As such, competition when applying to grad programs in these fields is fiercer than in others.

(that's what I understood after some reading of the forums here)

What are those fields in which there is more funding? Are they almost always fields which are less competitive?

I'm guessing some of those are biophysics and condensed matter. What about dynamical systems?